(i) Technical Field
A certain aspect of the embodiments discussed herein is related to an optical modulation apparatus, a method for controlling an optical modulator, and a control device for an optical modulator.
(ii) Related Art
In an optical communication system that superimposes a signal on a light and transmits the light with an optical fiber, an optical modulator that modulates the power of an laser light emitted from a light source, and generates an optical signal is used. For example, a Mach-Zehnder optical modulator is known as the optical modulator (See Japanese Patent Application Publication No. 07-049473).
The Mach-Zehnder optical modulator has a waveguide structure including a branch portion that branches an input light, two optical waveguides that propagate the branched lights, and a multiplex portion that multiplexs the lights propagated through the optical waveguides again. The Mach-Zehnder optical modulator is the optical modulator that turns on or off the light according to an interference condition at the time of multiplexing the lights.